Collapsible grid



Dec. 28 1926 o. PFEIFFER COLLAPSIBLE GRID Filed August 9. 1926 2 Sheets-Sheet 1 .T'ig. 2.

Dec. 28 ,11926. 1,612.771

Q. PFEIFFER v COLLAPSIBLE GRIb Filed August 9. 1926 2 Sheets-Shaaet 2 1 9 \lllllllllll I? ATTORNEY.

Patented Dec. 28, 1926.

UNITED STATES PATENT OFFICE.

OSW'ALD PFEIFFER, 0F LEIPZIG, GERMANY.

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Application filed August 9, 1926, SeriaI No.

I The invention relates to collapsible grids, for example grids used as guards for shop windows and the like, the grids being of the kind in which parallel stretcher bars are connected by bars perpendicular thereto, on

which they are slidable.

One object of the ing joints. grid of Another object is to provide a this kind whlch can, more conveniently than heretofore, be made of curved shape.

Further objects of the invention are to avoid joints which are liable to get out of order, and weaken the bars, and to enable the grid to be composed of parts which are simple and cheap to manufacture.

According to the invention the connecting bars joining successlve stretcher bars are disposed in series in which the connecting bars are offset in relation to each other, that is to say they are not in line but in echelon so that when the grid is collapsed side by side.

they lie Preferably each connecting bar is joined rigidly, by riveting or otherwise, to one of the which 1t connects;

two or more stretchers The stretchers may have apertures for passage of the connecting bar, the latter being, during the collapsing of the grid, able to pass freely through apertures in stretchers which they do not normally engage, but means being provided to prevent them from slipping through the stretchers located at their grid is extended. For this purpose made between the serially disjoints may be the apertures of ends when the sliding posed connecting bars. each joint consisting of a perforated or slotted arm pro ecting from one of the bars, and a head or enlargement on the other bar, which is unable to pass through the slot or hole.

The invention is illustrated in the drawings, which show device.

annexed an example of the Fig. 1 is a vertical section of part of the grid in the collapsed state, and

Fig. 2 is a similar section of part of the expanded grid.

Fig. 3 is a section of the line Fig. 2, and

ae of Fig. 4 a plan view, partly in section on the line 4-4 of Fig. 2.

Figure 5 is a perspective view of the 3 grid 128,128, and in Germany August 16, 1923.

showing the same partly in collapsed and expanded position.

The parallel horizontal stretcher bars 1 are channelled and have uniformly spaced and shaped rectangular apertures 2. These bars are connected to each other by vertical the part 4 each bar 3hasan elongated head 7, the web of the bar 1 traversed by the part 4 being held between this head and the collar 5. Except in regard to the collars 5 en--- gaging the top bar 1, each collar 5 is extended on one side to form an arm covering the aperture 2 next the one traversed by the part 4, and the arm has below the covered apertures a hole or slot 8 sufliciently large for slidable engagement with a bar 3, but not large enough for the passage of a stop gange or head 9 at the bottom of the said As shown in Fig. 2, successive bars 3 from top to bottom pass through the holes 9 in the collars 5 of the bars 3 below them, and are thus linked up with each other, though not disposed in vertical series, but offset, as shown.

For contracting the grid the lowermost bar 1 is lifted, which may be done by means of cords or chains with pulleys and a winch. When this bar meets the one above it it lifts the same to the next bar, which in turn is lifted, and so on. The bars 3 hang down within the vertical series of apertures 2 below the apertures in which their parts 4 are engaged.

It will be understood that the arrangement may be inverted in the sense that the parts 4, 5 and 7 are placed at the lower ends of the bars 3. and the parts 9 at the upper ends. in which case the bars 3 extend upwards from the bars 1 to which they are fixed, and collapse of the grid is allowed by lowering the top bar 1.

It will also be understood that for the sake of uniformity of manufacture the collars 5 on the bars 3 at the top may have lateral extensions on one side, similar to the others, though the same are not required.

In practice each of the bars 3 may be arranged so as to extend through any desired number of the bars 1 when the grid is extended.

The grid may be curved, as for instance for use with a curved shop Window, the bars 1 in that case being bent to conform to the curvature required.

In case; where it is preferred to have the grid horizontally collapsible the bars 1 are vertical, and the bars 3 horizontal.

Having now particularly described and ascertained the nature of my said invention and in what manner the same is to be performed, I declarethat what I claim is l. A collapsible and expansible grid comprising parallel stretcher bars, and rows or series of connecting bars xtending perpendicularly thereto, each connecting bar being fixed one end to a stretcher bar and slidably engaging at'least another stretcher bar and provided atits opposite end with means for limiting the spreadingdistance between the stretcher bars engaged at its ends when the grid is expanded, the connecting bars of each row or series being staggered with relation to the connecting bars of an adjacent row orroWS.

2. A collapsible and expansible grid comprising parallel stretcher bars having uniformly spaced apertures therein, plates fixed to said bars and extending between tWo adjacent apertures therein and provided with apertures registering With the apertures in the bars, connecting bars arranged at right angles to the stretcher bars, each connecting bar having a headed end extending through an aperture in one of the stretcher bars and the aperture in a plate registering therewith and fixed to said plate, said connecting bar slidably engaging an aperture in another stretcher bar and the aperture in the plate registering therewith, and a contact member on the other end of the connecting bar of greater size than the latternained apertures and adapted to abut against'the latter-named plate to limit the spreading motion of the bars when the grid is expanded.

3. A collapsible and expansible grid according to claim 2 wherein the stretcher bars are of channeled form and the plates are housed in the channels-thereof, and wherein the connecting bars are of I-be'am-section and the apertures in the plates are of corresponding I-forrn.

In testimony whereof I-afiix ny signature.

OSlVAL'D PFEIFFER. 

